Integrated circuits are commonly mounted in chip carriers which are bodies of insulating material having side surfaces to which conductors from the integrated circuit extend. Traditionally, terminal pads are provided on the side surfaces of the chip carrier body and contact is made with these pads to connect the integrated circuit to conductors on a substrate, such as a ceramic substrate or a circuit board. Electrical connection is usually established with the terminal pads on the chip carrier by means of a chip carrier socket which comprises a socket body having a recess which receives the chip carrier and contact terminals in surrounding relationship to the recess so that when the chip carrier is placed in the recess, the contact terminals electrically engage the terminal pads of the chip carrier.
Notwithstanding the relatively small size of the chip carrier socket and the contact terminals in the socket, it is necessary that each terminal be capable of exerting contact force on a terminal pad in a chip carrier in the range of about 200 to 400 grams in order to establish good electrical connection between the contact terminal and the terminal pad on the chip carrier, particularly if the terminal pad is tin plated rather than gold plated. It should also be noted that chip carriers and chip carrier sockets are subject to the dimensional variations which all mass produced parts are subjected to. These dimensional variation result from manufacturing tolerances. However, even with dimensional variations, the design and performance requirements discussed briefly above must be satisfied even in "worst case" conditions. For example, the minimum 200 gram contact force required for each contact must be met even if the particular terminal pad that a contact terminal engages is at the lower end of the tolerance range and the contact terminal similarly is at the lower end of the tolerance range for the parts.
For the new emerging family of modified gull wing chip carriers, a new socket is required than is found in the prior art. The contact force, etc. discussed above must remain the same in order to insure that a proper electrical connection is maintained.
It is therefore essential that a chip carrier socket be provided with the capability to insure that the appropriate force be exerted on the contact terminals. It is also extremely important that the contact force required for proper operation be provided in such a manner as to not require special tools for operation. The present invention is specifically directed to the achievement of an improved retention means which is capable of providing a reliable electrical connection between the contact terminals and the contact pads.